Carpenter Bee

Unlike other common bees, such as honey bees and bumble bees that live in colonies, carpenter bees are not social insects and build individual nests into trees or into the frames, eaves or sides of buildings.

Fast Facts

Color

Carpenter bees have a fuzzy, yellow thorax with a shiny, black abdomen.

Size

3/4-1" long, with females usually larger than males.

Appearance

Their body resembles a bumble bee, but has a smooth, rather than hairy, abdomen. Females have a stinger, but males do not.

Diet

Though carpenter bees, as their name would suggest, are commonly found in and around wood, the insects do not actually eat the timber. Like most bee species, carpenter bees forage on flowering plants, feeding on nectar. The females collecting pollen for their offspring.

Habitat & Nests

Unlike bumble bees, carpenter bees are solitary and do not live in nests or colonies. Adult carpenter bees overwinter in abandoned nest tunnels where they have stored limited pollen to survive the colder temperatures. The bees that survive the winter will emerge in the spring to feed on nectar, mate and build galleries. They may reuse an already existing gallery or they may excavate new galleries. Carpenter bee nests can often be found in decks, eaves, facia boards, doors, railings, window trim, and other wooden surfaces. They prefer the wood from redwood, cedar, pine, and cypress trees and target wood that is unpainted, untreated, and weathered. However, they occasionally target painted and primed wood as well.

The tunnels they excavate into wooden surfaces are only for nurturing their eggs and young. Nests usually consist of tunnels half of an inch in diameter and 6-10" deep and may include several brood chambers. Carpenter bees may buzz like saws when constructing nests (hence their name), but they do not eat the wood, as they cannot digest cellulose.

Colonies & Life Cycle

In contrast to the social tendencies of bumble and honey bees, carpenter bees lead solitary lives, as each female individually mates with a male to produce offspring. Mating takes place during the spring, and females then set to work cleaning out and enlarging tunnels left by earlier generations or excavate new ones in exposed, dry wood. Once there are enough chambers to accommodate six to eight eggs, females deposit a portion of pollen and regurgitated nectar to feed the larvae when they hatch, lay an egg and seal off the entrance with wood chips. Another plug of pollen is then added for numerous chambers per tunnel.

After the larvae complete pupation, newly mature adults emerge, usually in August. The life cycle from egg to larva to pupa to adult takes approximately seven weeks. There is only one generation a year, and individual bees overwinter and may live as long as three years.

Stings & Damage

Female carpenter bees can sting in defense if provoked, but males, which may appear a bit more aggressive and territorial, cannot sting. It may be surprising to learn that this is one of the least aggressive stinging insects encountered in the summer months.

Carpenter bees are considered pests because they drill holes in wooden structures; however, their contribution to pollination far outweighs any damage to structures. In general, carpenter bees do not pose much of a problem for homes and businesses, but generations of carpenter bees tunneling into the same wood can lead to significant structural damage. The carpenter bee produces broods that return to the same nest location to begin additional nests, creating trouble for those with an infestation. Additionally, the larvae developing in homes are attractive to woodpeckers and create more extensive damage to the existing holes while creating unwanted noise.

Signs of Infestation

Holes

The most common sign of a carpenter bee infestation are the round, smooth holes about 1/2" in diameter that carpenter bees bore into wood. There may also be evidence of sawdust.

Sighting

A notable sign of infestation are the male carpenter bees that hover around nesting sites in the spring and summer flying aggressively at intruders.

Stains

The wood around entrance holes may be stained with feces.

Prevention & Control

Carpenter Bee Prevention

Finish Wooden SurfacesSince carpenter bees attack unfinished and unpainted wood products, the best way to prevent the pests from becoming a problem is to ensure all wooden furniture and fixtures are varnished, finished and painted.

Seal CracksTo prevent carpenter bees from entering the home, seal cracks and crevices along the property’s foundation and walls with a silicone-based caulk, repair any tears in screens, and keep doors closed at all times.

Inspect Purchased ObjectsProperty owners and residents should also closely inspect wooden products for signs of a carpenter bee presence before purchasing.

Regular inspections of your home by a pest control professional throughout the year is the best method to identify and prevent any issues with carpenter bees or any other pests. The BAN System provides regularly scheduled preventive services every quarter.

Carpenter Bee Control

The places on a home that are the most attractive for carpenter bees to create their holes are often the out-of-site, out-of-mind areas that can be inaccessible or difficult to reach, as they are more likely to have water damage, untreated wood, etc. Do not simply seal the holes and paint over them, as this will cause the carpenter bee hatchlings to try to escape in ways that can cause more damage to the structure. It is advised that a pest control professional assess the situation and offer solutions that will prevent incidents like this from occurring. A professional has the knowledge to inspect the property for galleries and choose the appropriate treatment method.

A Batzner Service Specialist will identify the locations of potential nesting sites by focusing on key areas (untreated, unpainted, soft, or moisture damaged wood) and looking out for frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects), small round drill holes, and other evidence of carpenter bee activity. The best approach to treating the nests will be determined by several factors, including their location and level of activity.